Study of the Coordination Modes of Hybrid NNCp Cyclopentadienyl/Scorpionate Ligands in Ir Compounds

Inorg Chem. 2019 Jan 7;58(1):900-908. doi: 10.1021/acs.inorgchem.8b03030. Epub 2018 Dec 12.

Abstract

A new coordination mode for the hybrid scorpionate/cyclopentadienyl ligand bpzcp, [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] is observed in iridium complexes. The reaction of the lithium precursor, [Li(bpzcp)(THF)], with a range of [IrCl(diene)]2 compounds leads to an unprecedented binding mode of the hybrid scorpionate/cyclopentadienyl ligand as η5-Cp-coordinated and the formation of Ir(I) derivatives [Ir(η5-Cp-bpzcp)(η4-cod)] (1), [Ir(η5-Cp-bpzcp){η4-CH2═C(Me)C(Me)═CH2}] (2), [Ir(η5-Cp-bpzcp)(η2-coe)2] (3), and [Ir(η5-Cp-bpzcp)(η2-CH2═CH2)2] (4). The Ir(I) complex 4 reacts with CO or bromine to afford the compound [Ir(η5-Cp-bpzcp)(CO)2] (5) and the 18e- Ir(III) complex [Ir(κ-N-η5-Cp-bpzcpBr2)Br2] (6), respectively. Reaction of the iridium compounds (2-4) with CuI or [PdCl2(CH3CN)2] yields the heterobimetallic iridium-copper or iridium-palladium complexes [Ir(η5-Cp-bpzcp){η4-CH2═C(Me)C(Me)═CH2}(μ-bpzcp){CuI(κ2-NN-bpzcp)}] (7), [Ir(η5-Cp-bpzcp)(η2-coe)2}(μ-bpzcp){CuI(κ2-NN-bpzcp)}] (8), [Ir(η5-Cp-bpzcp)(η2-CH2═CH2)2}(μ-bpzcp){CuI(κ2-NN-bpzcp)}] (9), [Ir(η5-Cp-bpzcp)(coe)2}(μ-bpzcp){PdCl22-NN-bpzcp)}] (10), and [Ir(η5-Cp-bpzcp)(η2-CH2═CH2)2(μ-bpzcp){PdCl22-NN-bpzcp)}] (11). All products were characterized by spectroscopic methods and the X-ray crystal structures of 1, 2, 3, 4, and 6 were also established.